1. Field of the Invention
The present invention relates to an improved library storage system. More particularly, the present invention relates to a system for adding intelligence to the tape drive tray subassembly in order to provide better control, monitoring, and diagnostics of a library's subsystems.
2. Background of the Invention
Existing automated storage libraries are capable of storing and retrieving large quantities of information stored on media cartridges. This capability is accomplished by the use of a large number of drive trays, each of which houses a tape drive, that are installed within a library frame. Electrical connections cabled between the tape drive trays and the main library controller or processor provide the main library controller with the means to control and monitor tape drive tray functions.
Designing the interface to monitor and control the tape drive tray subassembly can be a complex endeavor in systems having large enterprise libraries. Currently, customer demands for high availability in the enterprise tape library market require more monitoring of the library's subsystems. As the enterprise market targets larger and larger libraries, designing the electrical and mechanical infrastructure needed to control and monitor these subsystems becomes a challenging issue.
A conventional tape drive array includes a number of tape drive trays installed in a tape library frame. FIG. 1 depicts an example of a large-scale tape library system which supports 64 tape drive trays. Tape drive trays 102 are grouped into tape drive arrays 104. Each tape drive tray 102 is connected to the main library controller 106. Each connection line 108 as shown in FIG. 1 represents multiple signals. Electrical connections between main library controller 106 and tape drive trays 102 provide main library controller 106 with the means to control and monitor tape drive tray functions.
In view of current demands for high availability in the enterprise tape market, conventional tape drive systems contain several disadvantages. One such disadvantage is that as the number of supported tape drive trays increases, more of the library's main controller's bandwidth is required to monitor and control the tape drive trays. For example, the library system as shown in FIG. 1 may require that fans, temperature, and power supply status, as well as software controlled power-on, be monitored for each of the 64 tape drive trays.
Another challenge encountered in designing large-scale libraries is that as the number of tape drives increases, the number of signals between the main library controller and the tape drive array becomes extremely large. This is an important issue for tape subsystems that support a large number of tape drives (e.g., up to 64 tape drives). Since each tape drive tray interface typically contains fifteen signals, almost one thousand signal connections to the main library controller are required if each drive tray signal is connected directly to the main controller. Physically connecting and routing all of these signals are difficult and costly.
Furthermore, current methods for adding features to a conventional drive tray system typically require adding new signals to the drive tray cabling. As a result, it may be difficult to add features to the drive tray at a later point in time. For systems designed for high availability, adding new signals to the drive tray cabling is problematic because the library must be shut down to make the necessary changes.
Consequently, it would be advantageous to have a system for providing local control and monitoring of a tape drive's subsystems in order to overcome the electrical and mechanical issues encountered in high availability enterprise libraries in the prior art. It would further be advantageous to have a system that provides flexibility for the addition of future features.